Devices KT1000 and KT2000 sold by MEDmetric® Corporation are known in the market and they roughly measure the anterior and posterior tibial translation, which is measured from the outside of the leg and has the muscle mass and the soft tissues (more or less compressible and variable from individual to individual) as an error factor, being this measurement taken only in mm.
Ferromagnetic materials are used in these devices, what makes them unusable inside MRI or CAT-scan devices is they interfere with the image processing. These devices are used only for evaluation of the anterior cruciate ligament rupture and posterior cruciate ligament rupture.
EP 1 125 567 discloses a device allowing an accurate measuring of the tibial anterior translation and internal rotation because it can be used inside MRI or CAT-scan devices, not interfering with image processing since it doesn't include ferromagnetic materials.
The measurements are made in the MRI or CAT-scan images, between two bone structures (femur and tibia) which grants them great accuracy. These measurements can be related to the associated injuries observed in the images (meniscus, cartilage, etc.).
This device disclosed in patent EP 1 125 567 is only used in the ruptures of the anterior cruciate ligament. On account of this uniqueness, it doesn't allow an accurate diagnosis of associate instabilities.
On account of those limitations, the device disclosed in patent EP 1 125 567 does not allow distinction of those patients who need a surgical technique with greater or lesser rotation control, and also does not allow the evaluation of patients with associate ligament injuries (most common).
The device described in this invention allows an accurate measuring of the tibial anterior translation and tibial posterior translation, the internal rotation and external rotation because it can be used inside devices of MRI or CAT-scan, not interfering with image processing since it doesn't include ferromagnetic materials.
The device for measuring the knee laxity described in the invention includes materials suitable for use in MRI or CAT-scan for instance, inter alia, composites, plastics, resins and carbon fibers.
With the assistance of the device described in this invention, the measurements are made in the images from MRI and CAT-scan between two bone structures, femur and tibia.
These measurements can be related to associated injuries observed in the images, like inter alia, with meniscus, cartilages, etc.
The device for measuring the knee laxity described in the present invention has the ability to measure the knee rotation without using images from MRI and CAT-scan.
The device is used for ruptures of the anterior cruciate ligament and posterior cruciate ligament, antero-external, postero-external, antero-internal and postero-internal instabilities, instabilities in all directions, and also to evaluate all possible rotational instabilities of the knee.
It is therefore possible to obtain accurate diagnoses and subsequent modifications of the surgical indications, allowing the separation of those patients who need surgery from those who just need physiotherapy.
This device is quite innovative and will radically change the orthopedics market since:                Until now, with prior art technique, the instability measurement is made roughly and by approximation, while with this new device it will be possible to measure the knee instability with accuracy.        Until now, the treatment and surgeries for knee traumatic injury were generic, but with this new device it will be possible to get and set a real diagnosis, leading to more appropriate treatments which means one can decide whether or not to perform surgery with greater precision, and can choose between different types of surgery depending on the needs, leading to a higher success rate in patients' recovery.        